Cleaning spray nozzles



, Aug. 18, 1959 w. J. MONROE 2,899,929

CLEANING SPRAY NOZZLES Filed Nov. 7, 1957 TO VACUUM g 29 1 I f T. =:ll 2| Mam; fi /g lvebi CLEANING SPRAY NOZZLES William J. Monroe, Ford City, Pa., assignor to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Application November 7, 1957, Serial No. 694,986

Claims. (Cl. 118302) Thisapplication relates to improvements in cleaning spray nozzles and specifically relates to the use of freely rotatable brushes to clean the orifices of reciprocating spray guns used to spray coatings on sheet material, for example, glass sheets. In a specific embodiment, the brushes are located in alignment with an extremity of the path of reciprocation for each spray gun orifice. As the spray gun reaches one extremity of its reciprocating movement, its orifice contacts the bristles of the freely rotatable brush to wipe the orifice clean and prevent caking of the coating composition sprayed through the orifice by the spray gun.

The objects and advantages of the present invention will be better understood in the light of the detailed description of a particular embodiment which follows.

In the drawings which form part of the present disclosure,

Figure 1 is an elevational view of a typical apparatus for spraying a surface of sheet material'suchas moving glass sheets and incorporating the present invention; and

Figure 2 is an enlarged, fragmentary, detailed perspective view showing the details of the brush and the orifice portion of the spray gun.

The spray apparatus or chamber, depicted generally by reference character 10, comprises a transverse beam 12 extending across the spray apparatus above a conveyor C to support a drive chain 14 between a pair of sprockets 16 carried by the beam 12. A carriage 18 is mounted for reciprocation on the transverse beam 12 by connecting a lug 20, slidably mounted in a vertical slot 21 of the carriage 18, to a link of the drive chain 14. As the sprockets 16 rotate, they move the drive chain 14 and lug 20 to impart a reciprocating movement to carriage 18 along the transverse beam 12.

Each carriage 18 is provided with a depending bracket 22 for carrying one or more spray guns 24, each having an orifice 25. Binks model 21 spray guns have been used in commercial operation. Flexible supply hoses 26, supported by a hook 28 fixed to the roof 29 of the spray chamber are used to deliver various ingredients to the spray guns 24. These ingredients are mixed in the spray gun to provide a spraying composition. The spray guns 24 are valved to control the flow of ingredients for the spray composition.

In the event multiple spray guns are used, the actuation of the valves is synchronized by interconnecting the moving elements of each valve to a common actuation bar. Since this type of multiple spray apparatus does not form part of the present invention, except that provision should be made to wipe clean the orifice of each spray gun, the description of the particular details of the multiple spray gun construction is omitted.

A vacuum exhaust chamber 30 is locatedat one side of the spraying apparatus 10 and includes an apertured wall 31 adjacent the spray chamber 10. A water feed pipe 32 containing spaced apertures 33 is carried by an oblique wall 34 within the vacuum exhaust chamber 30. Apertured oblique walls 35 and 36 extend outboard of 2,899,929 Patented Aug. 18,

wall 34. A trough 37 is located at the bottom of chainber 30. A water outlet pipe 38 extends from the bottom of trough 37 to a conventional recovery system (not shown). An air exhaust pipe 39 extends from the top of chamber 30 to a vacuum pump (not shown).

The spray guns 24 are reciprocated with the carriage I 18 as the drive chain 14 moves the lug back and forth relative to the path of movement of the material being coated. The spraying composition used to coat glass sheets is a frit dispersed in a volatile carrier. Such a spraying composition is likely to cake at the spray gun orifice unless the composition is cleaned periodically from the orifice. Manually cleaning the orifices'is impractical, because the time required for manual cleaning interferes with continuous coating operations where sheets are. conveyed continuously through a spray chamber for the coating operation. If the spray gun orifice is not wiped frequently, the coating composition tends to cake 'at'the orifice and, from time to time, the spray gun dispenses a small agglomeration of *frit, causing spottiness in the sheet coated. The present invention inhibits caking of the spray composition at a nozzle orifice.

One of the posts 40 for supporting the conveyor C on which articles are transported through the spray chamber 10 is located adjacent the vacuum exhaust chamber 30. Attached to the post- 40 and extending vertically upwardly therefrom is a rod-like member 42, which terminates at its upper extremity in a ball hearing housing 44 within which a ball bearing 46 is located. A disc 48 is mounted for free rotation with respect to the ball bearing and comprises a circular chan nel 50 fixed to its upper surface for clamping vertically extending brush bristles 52 thereto. The brush bristles are preferably nylon and are mounted to form a ring of bristles clamped to the circular channel 50.

As the spray gun 24 reaches an extremity of its reciprocating movement defined by the drive chain 14, its orifice 25 contacts the nylon bristles 52 causing the brush to rotate freely about a vertical axis. Thus, the nozzle orifice 25 is wiped clean each time the spray gun 24 touches the brush bristles 52.

Oscillation of the brush bristles resulting from contact with the spray gun orifice 25 causes spattering of any caked agglomeration of the spraying composition wiped from the orifice. The suction of the vacuum exhaust chamber 30 removes the spattered agglomeration from the spraying apparatus 10. Therefore, the agglomeration 'does not fall inadvertently onto the surface of an article conveyed through the spray chamber for coating. The evacuated agglomerates are mostly captured by the water cascading down the oblique wall 34 and carried to a recovery system. The remainder of the unused spray composition is evacuated from the spray apparatus 10 through the air exhaust pipe 39.

By virtue of the present invention, the spray gun orifice 25 is cleaned upon each cycle of reciprocation by the spray gun and it has become unnecessary to interrupt high speed production of coated articles to remove for reciprocating the, spray means across the width of said sheet material and a freely rotatable brush having bristlesaligned with an extremity of the path of reciprocating for each spray means and so located with respect to said path to enable the bristles to wipe the spray means each time the spray means reaches said extremity.

2. In apparatusfor spraying a surface of sheet material comprising a spraying station including horizontally disposed sheet support means, spray means disposed above said support means for applying a liquid dispersion of 'a coating composition onto a surface of said sheet material, means for reciprocating the spray means across the width of said sheet material and a freely rotatablebrushhaving' bristles aligned with an extremity of the. path of reciprocating for each 'spray means and so located with respect to said pathtoenable the bristlesto wipe the spray means each time the spray means reaches said'extremity.

3 In apparatus for spraying a surface of moving glass sheets comprising horizontally disposed conveyor means extending longitudinally thereof for transporting fiat glass sheets therealong, at least one spray gun disposed above said conveyor means and having an orifice for applying a liquid dispersion of a coatingcomposition through said orifice onto the upper surface of said glass sheets, means for reciprocating the spray guns across the path I exhaust means disposed on the side of the apparatus where the brushes are located for removing agglomerations of coating material from the vicinity of the conveyed glass sheets.

References Cited in the file of this patent UNITED STATES PATENTS 2,028,355 Russi Jan. 21, 1936 2,086,514 Saunders et al. July 6, 1937 2,293,881 Bailey Aug. 25, 1942 2,357,824 Haywood Sept. 12, 1 944 2,488,518 Andrews et a1. Nov. 22, 1949 2,736,290 Scholl u Feb. 28, 1956 2,815,298

Hefiley Dec. 3, 1957 

